Consider an aluminum fabrication plant with 400 employees that runs on three shifts for a total of 8,760 hours per year. The company spent $1.1 million in electric energy bills last year. The plant uses numerous motors to drive process-related equipment such as shell presses and compound presses. Determine if it is cost-effective to replace the existing motors with high-efficient motors under the following three rate structures:

For all the rates, the utility company charges the facility an average cost of electricity, without demand, of $0.05/kWh. The demand charges are:

a. Rate 1: 7.02/kVA

b. Rate 2: $5.00/kW (billed demand)

c. Rate 3: $5.00/kW plus $0.75 for excess KVAR above 6 percent of real demand The motors that will be replaced are listed below.

Transcribed Image Text:

Hp 100 60 40 20 15 10 7.5 5 2 1.5 LFa 0.75 0.75 0.50 0.50 0.50 0.50 0.50 0.50 0.50 2 0.50 N 4 2 13 2 12 5 57 43 14 eff-s eff-e 0.919 0.950 0.916 0.940 0.908 0.934 0.886 0.923 0.759 0.875 0.916 0.681 0.864 0.910 0.714 0.846 0.902 0.683 0.839 0.890 0.687 0.791 0.864 0.516 0.780 0.852 0.546 pf-s pf-e 0.872 0.905 0.854 0.861 0.797 0.805 0.833 0.774 0.770 0.731 0.714 0.540 0.580